Mehh I can give some Sci Fi Suggestions though you seem to be oriented more towards the action side: (Oh and the Planetes author is doing Vinland Saga, its scanlated by mangascreener and its in the same vein as berserk in terms of fantasy/action.)

Please Save My Earth - Shoujo/Drama/Sci fi/Psychic/Romance
Perhaps not your cup of tea but its pretty much an uber manga for a shoujo manga. A girl has weird dreams of another life as an alien overlooking the earth. She finds other people at the school have also have had these recurring dreams. As they start to learn more and more of their past lives on a tragic station slowly dieing one by one, with their home planet destroyed by a civil war. Meanwhile a few start developing psychic powers, and the past lives loves and hates start to take them more and more. Are they doomed to repeat their past lives... or will they manage to find new lives, and not fight again amongst themselves.
The hawks did the scanlation so you can find a bit torrent there or box torrents, my http link for it has dried up.

Level E - Comedy/Sci Fi
If you haven't read this off the site you missed out. If dark humor is at all your thing this mangas pretty damn hilarious. "about aliens residing on Earth and their interactions with humanity. Its twisted sense of humor and excellent characters make it well worth the download!"(jinmen-juushin site)

Pluto - Drama/Sci Fi
"In Naoki Urasawa’s Pluto we have a story arc from the classic Astro Boy (or Tetsuwan Atom) series that is taken, refined, and retold." It's basically a hardboiled crime detective manga in a futuristic world hunting for a robot killer who has been killing all the famous robot heroes. It's definitely not a kiddy manga though, its Urasawa, the writer of Monster's, take upon the world. http://souhaku.ufpag.com/index.php?m...age&PAGE_id=28

Thats all I can think off tof the top of my head. Also 20th centuries boys is vaguely scifi if you haven't tried it, its a prety good seinen.

Hmm...
Forgot to mention Level E
Read some of Escaflowne, but don't have scans, Don' have GITS, read it though, Read some of RahXehon, also don't have scans, Read some Gundam, but on average I can't stand the horrible Physics, Read some of Pluto, wasn't really interested in it, and didn't like Please Save My Earth.